The telescopic tube structure comprises an outer tube, an inner tube elastically sleeved by said outer tube and a locking structure for locking two adjacent connection tubes into an integral piece. The locking structure of prior arts only has a locking function, but does not have a waterproof function, when the telescopic tube is used in the water, water and sand will enter the telescopic tube, this may lead to an unsmooth telescopic effect between the inner tube and the outer tube, even damage to the internal components.
The telescopic tubes are usually used on tripod of photographic equipments. In the field of photographic equipment, a foot tube of a tripod is usually in the form of a telescopic tube, in order to solve the problem of non-watertight locking structure of foot tube in the prior art, Chinese patent CN201651699U discloses a locking waterproof structure of leg tubes, comprising a threaded sleeve tube, a rubber sleeve, a locking part and a locking knob component, the upper portion of the threaded sleeve tube is connected with an upper tube of a tripod leg tube, a holding cavity with the opened lower end is formed between the lower portion of the threaded sleeve tube and a lower tube of the tripod leg tube, the locking part is sleeved onto the lower tube and arranged in the holding cavity, the rubber sleeve is sleeved on the upper portion of the threaded sleeve tube, the locking knob component comprises a lock ring sleeve and a rubber part coated outside the lock ring sleeve, the lock ring sleeve is fittingly connected with the threaded sleeve tube in a thread manner, the bottom end of the rubber part is provided with a rubber part converging portion which is in interference fit with the lower tube, and the thickness of the rubber sleeve meets the requirement that the upper end of the inner wall of the lock ring sleeve and the outer wall of the rubber sleeve are in interference fit after the rubber sleeve is locked through rotating the locking knob component.
The waterproof of the lower end of the locking waterproof structure of leg tubes in the above patent document is achieved by providing a rubber sleeve at the lower end face of the lock ring sleeve, the sealing between the locking ring sleeve and the lower tube is achieved by the interference fit between the rubber part converging portion and the lower tube, during the telescopic adjustment between the upper tube and the lower tube, the rubber part converging portion is easy to be abraded, therefore the interference fit is easy to be destroyed, which eventually affects the sealing between the rubber part and the lower tube, thus, leads to a poor waterproof effect, besides, the exposed rubber part may lead to an external abrasion and corrosion, even can be peeled off from the end face, so that the waterproof performance of the locking structure is affected and even lost.